1. Field of the Invention
This invention relates to a driving apparatus for a two-for-one twister wherein a left train and a right train each including a downwardly located spindle train and an upwardly located take-up mechanism train are disposed in a back-to-back relationship to each other.
2. Prior Art
The construction of a two-for-one twister of the type mentioned will be described with reference to FIGS. 3 and 4. Referring first to FIG. 4, the two-for-one twister 1 includes a right train 52 and a left train 53 each including a downwardly located spindle train 50 and an upwardly located take-up mechanism train 51 and disposed in a back-to-back symmetrical relationship to each other. Referring now to FIG. 3, a driving apparatus for the two-for-one twister includes a belt apparatus 9 for the spindle trains 50, and a speed changing device 10 for the take-up mechanism trains 51. The entire driving apparatus is driven by a motor 11 common to the right train 52 and the left train 53.
Referring to FIG. 3, the spindle train 50 has a structure wherein a spindle 3 extends outwardly from each of a plurality of covers 2 each provided for accommodating a supply yarn package therein. The spindles 3 are held in contact with the tangential belt 4 so that they are rotated at a high speed by the tangential belt 4. The spindles 3 in the left and right trains are driven by the single tangential belt 4 as seen from FIG. 5. A yarn supplied from each supply yarn package is introduced into a tension apparatus disposed above the corresponding spindle 3, in which tension is applied to it, and then, it is twisted by two twists while it is ballooned by a rotary disk which rotates together with the spindle 3.
Meanwhile, the take-up mechanism trains 51 are constructed such that each twisted yarn is taken over by a feed roller 8 and then traversed by a traverse guide 7 which is reciprocated, whereafter it is taken up onto a take-up package 5 which contacts with and is rotated by a corresponding drum 6. The left and right take-up mechanism trains 51 can be adjusted so as to provide different numbers of twists to yarns by way of a pair of different belt speed changing devices 30. To this end, a pair of pulleys 17 are disposed at different locations in a direction perpendicular to the plane of FIG. 3, and also a shaft 20 and several components having reference numbers beginning with 30 for the belt speed change bears are each provided in pair at locations in the direction perpendicular to the plane of FIG. 3. It is to be noted that a belt 18 for the two pulleys 17 extends to and around a common second pulley 14.
Subsequently, details of the driving apparatus for driving the belt apparatus 9 for the spindle trains and the speed changing device 10 for the take-up mechanism trains by the common motor 11 will be described. The driving motor 11 has an output shaft 12 on which a pair of first and second pulleys 13 and 14 are securely mounted, and a belt 16 extends between and around the first pulley 13 and a third pulley 15 while another belt 18 extends between and around the second pulley 14 and a fourth pulley 17. The third pulley 15 is securely mounted on a shaft 19, which is connected to the belt apparatus 9, and the fourth pulley 17 is securely mounted on another shaft 20, which is connected to the speed changing device 10.
The belt apparatus 9 for the spindle trains is constructed such that the tangential belt 4 of an endless configuration extends between and around a fifth pulley 21 serving as a driving pulley and a sixth pulley 22 serving as a turn pulley. The fifth pulley 21 and the third pulley 15 are securely mounted at the opposite ends of the shaft 19, and output power of the driving motor 11 is transmitted to the tangential belt 4 by way of the output shaft 12, the first pulley 13, the belt 16, the third pulley 15 and the fifth pulley 21 so that the belt 4 is circulated to rotate the spindles 3. As seen from FIG. 5 which is a sectional view taken along line V--V of FIG. 3, the left and right spindle trains 3 are held in rolling contact with both of the slackening side portion and the tensioning side portion of the tangential belt 4. A belt tensioner 23 is disposed to contact with the slackening side portion of the tangential belt 4.
The speed changing device 10 for the take-up mechanism trains has the following structure. Each of the fourth pulleys 17 is securely mounted at an end of the corresponding shaft 20, and the other end of the shaft 20 is connected to the speed change belt apparatus 30. A plurality of gear wheels are installed in a reduction box 31, and rotating power from an output shaft 32 of the speed change belt apparatus 30 is inputted to the reduction box 31. The reduction box 31 thus reduces the speed of the input rotating power at a fixed rate and changes the direction of rotation of the input rotating power. A seventh pulley 34 is securely mounted on an output shaft 33 of the reduction box 31. A belt 39 extends between and around the seventh pulley 34 and an eighth pulley 36 securely mounted on a support shaft 35 by way of a ninth pulley 38 securely mounted on another support shaft 37. The drums 6 are securely mounted on the support shaft 35 in a predetermined spaced relationship from each other, and a treble gear 40 is securely mounted at an end of the support shaft 35. Meanwhile, the feed rollers 8 are securely mounted on the other support shaft 37 in a predetermined spaced relationship from each other. A belt 43 extends between and around the treble pulley 40 and another treble pulley 42 securely mounted at an end of a shaft 41. The other end of the shaft 41 extends into a cam box 25, and the shaft 41 is connected to a grooved drum 46 by way of a pair of gear wheels 44 and 45. The drum 46 has a cam groove 47 formed thereon, and a cam shoe 48 is fitted in the cam groove 47. A reciprocatory rod 49 is securely mounted on the cam shoe 48, and the traverse guides 7 are Securely mounted on the rod 49 in a predetermined spaced relationship from each other. As seen from FIG. 4 which is a sectional view taken along line IV--IV of FIG. 3, the elements having reference numerals equal to and greater than 34 for the seventh pulley are disposed in the two left and right symmetrically arranged trains. With the construction described above, output power of the driving motor 11 is transmitted by way of the belt 18, the speed change belt apparatus 30, the reduction box 31 and the belt 39 to the support shaft 35 for the drums 6 and the support shaft 37 for the feed rollers 8 to rotate the drums 6 and the feed rollers 8. Rotation of the support shaft 35 is further transmitted by way of the belt 43 to the grooved drum 46 to rotate the drum 46, whereupon the cam shoe 48 is moved along the groove 47 of the drum 46 to reciprocate the traverse guides 7.
Since the driving apparatus for a two-for-one twister described above has the structure wherein the left and right trains are driven by the common motor, neither of the left and right trains can be driven solely. Meanwhile, as the tendency of production of many kinds by small amounts in recent years increases, such a demand as to drive individually each of the left and right trains 52 and 53 of FIG. 4 has arisen. Here, it seems a promising idea to, for example, dispose the belt apparatus 9 for the right spindle train and the speed changing device 10 for the right take-up mechanism train at an end of the machine base while the belt apparatus 9 and the speed change gear 10 for the left train are disposed at the other end of the machine base. However, this requires a pair of driving apparatus disposed at the opposite ends of the machine base, and consequently, there is a problem in that the locations for maintenance are dispersed. Particularly, the speed changing device 10 for the take-up mechanism trains involves a large number of gear wheels, belts and like elements, and accordingly, the location of it is dispersed, resulting in inconvenience for maintenance. Also, it seems promising to dispose a pair of belt apparatus 9 for the left and right trains separately on the opposite sides of the machine base and connect a pair of speed changing devices 10 for the left and right trains to one of the belt apparatus 9 for the spindle trains. However, although the speed changing devices 10 for the left and right spindle trains start or stop simultaneously with each other, the belt apparatus 9 for the left and right trains 9 start or stop at different timings from each other, and accordingly, non-twisted portions or excessively twisted portions may possibly be produced at starting or terminating ends of yarns.